Relationship between structural and dielectric properties of Znsubstituted Ba5CaTi2−xZnxNb8O30 tetragonal tungsten bronze

Amine Bendahhou (1) , Pascal Marchet (2, 3) , Ablouh El-Houssaine (4) , Soufian El Barkany (5) , Mohamed Abou-Salama (1)

1 Faculté Pluridisciplinaire de Nador
2 IRCER - Institut de Recherche sur les CERamiques
3 IRCER-AXE3 - IRCER - Axe 3 : organisation structurale multiéchelle des matériaux
4 UCA - Université Cadi Ayyad [Marrakech]
5 IRCER-AXE1 - IRCER - Axe 1 : procédés céramiques

Ba5CaTi2-xZnxNb8O30 ceramics with (x=0, 0.04, and 0.08) were synthesized by conventional solid-state reaction method at 1300°C for 6 hours. The effects of the Ti/Zn ratio on structural and dielectric properties were studied by changing the value of x. The pure phase formation of all prepared Ba5CaTi2-xZnxNb8O30 compositions was confirmed by X-ray diffraction. The refinement of the (XRD) data by the Rietveld method confirmed the tetragonal crystal structure with the space group P4bm at room temperature. Scanning electron microscopy (SEM) of Ba5CaTi2-xZnxNb8O30 ceramics shows good sinterability, low porosity and uniform distribution of grains of unequal size over the entire surface in all samples. The average grain size is in the range of 1.3 to 1.6 μm. The frequency-dependent dielectric properties were examined by complex impedance spectroscopy in the temperature range of 50°C to 420°C where a structural phase transition was observed for all samples.

Mots clés: Tetragonal tungsten bronze; Ceramics; Solid state reaction; X-ray diffraction; Structure; Phase transition; Dielectric properties

Domaines: Matériaux; Cristallographie

Amine Bendahhou, Pascal Marchet, Ablouh El-Houssaine, Soufian El Barkany, Mohamed Abou-Salama. Relationship between structural and dielectric properties of Znsubstituted Ba5CaTi2−xZnxNb8O30 tetragonal tungsten bronze. CrystEngComm, 2021, 23 (1), pp.163-173. ⟨10.1039/D0CE01561J⟩. ⟨hal-03144653⟩